Devices such as mobile cellular telephones usually include signal processing apparatus (for example, circuitry such as delay lines, memories, correlators and filters) that may provide a variety of functions. For example, a delay line may include a material that converts an electrical signal to an acoustic signal at one end and converts the acoustic signal to an electrical signal at the opposite end. Since the speed of the acoustic wave is slower than the speed of the equivalent electrical signal, a delay is created in the reception of the signal.
In order for such signal processing apparatus to process a signal sufficiently, the circuitry may require a relatively large space in the apparatus. However, in some devices such as mobile cellular telephones, there is currently a desire to reduce the size of the device. The volume required for the signal processing apparatus may result in the device having an undesirable relatively large size.
It would therefore be desirable to provide an alternative apparatus.